1. Field of the Invention
The present invention relates to a light-emitting diode and a fabricating method thereof, and more particularly, the present invention relates to a light-emitting diode with high luminescent efficiency and the fabricating method thereof.
2. Description of the Prior Art
So far, light-emitting diodes have been broadly applied to various products such as key switch systems, back-light modules of mobile phones, lighting systems of vehicles, light bulbs for decorations, and remote controls, etc. In order to make sure light-emitting diodes have properties of high reliability and low energy consumption, the luminescent efficiency of a light-emitting diode is regarded as one of the most important items.
Please refer to FIG. 1 which is a cross-sectional view illustrating a conventional light-emitting diode. The conventional light-emitting diode 1 including a substrate 10, an N-type gallium nitride layer 11, a luminescing layer 12, a P-type gallium nitride layer 13, and electrodes 14, 15. The conventional light-emitting diode 1 operates by means of conducting the P-type gallium nitride layer 13 and the N-type gallium nitride layer 11. The electrode 15 is formed on the P-type gallium nitride layer 13 and the electrode 14 is formed on the N-type gallium nitride layer 11.
Generally, the luminescent efficiency of a light-emitting diode is relative to its inner quantum efficiency and light-extraction efficiency. So-called inner quantum efficiency is determined by the characteristics and properties of a material. As for light-extraction efficiency, it means the ratio of radiation emitted from the inner light-emitting diode to the surrounding air or the surrounding epoxy resin packaging the light-emitting diode. Although light-emitting diodes with various structures have been brought up by now, how to fully improve the light-extraction efficiency and the luminescent efficiency of a light-emitting diode is still an important issue.